Series
2000
Magnehelic® Differential Pressure
Gages
Indicate positive, negative, or differential. Accurate within 2%
Service Manual
Dimensional Enlargement
Select the Dwyer Magnehelic gage for high accuracy - guaranteed within 2% of full scale - and for the wide choice of 81
ranges available to suit your needs precisely. Using Dwyer's simple, frictionless Magnehelic movement, it quickly
indicates low air or non-corrosive gas pressures--either positive, negative (vacuum) or differential. The design resists
shock, vibration and over-pressures. No manometer fluid to evaporate, freeze or cause toxic or leveling problems. It's
inexpensive, too.
Widely used to measure fan and blower pressures, filter resistance, air velocity, furnace draft, pressure drop across orifice
plates, liquid levels with bubbler systems and pressures in fluid amplifier or fluidic systems. It also checks gas-air ratio
controls and automatic valves, and monitors blood and respiratory pressures in medical care equipment.
MOUNTING. A single case size is used for most ranges of Magnehelic gages. They can be flush or surface mounted
with standard hardware supplied. With the optional A-610 Pipe Mounting Kit they may be conveniently installed on
horizontal or vertical 1¼" - 2" pipe. Although calibrated for vertical position, many ranges above 1 inch may be used at
any angle by simply re-zeroing. However, for maximum accuracy, they must be calibrated in the same position in which
they are used. These characteristics make Magnehelic gages ideal for both stationary and portable applications. A 4 9/16"
hole is required for flush panel mounting. Complete mounting and connection fittings plus instructions are furnished with
each instrument.
Vent valves
In applications where pressure is continuous and the Magnehelic gage is connected by metal or plastic tubing
which cannot be easily removed, we suggest using Dwyer A-310A vent valves to connect gage. Pressure can
then be removed to check or re-zero the gage.
High and medium pressure models
Installation is similar to standard gages except that a 4 13/l6" hole is needed for flush mounting. The medium
pressure construction is rated for internal pressures up to 35 psig and the high pressure up to 80 psig.
Available in all ranges. Because of larger case, will not fit in portable case. Weight 1 lb., 10 oz. (Installation
of the A-321 safety relief valve on standard Magnehelic gages often provides adequate protection against infrequent
overpressure; see Bulletin S-101).
PHYSICAL DATA
Ambient temperature range: 20° to 140°F.* (-7° to 140°C)
Rated total pressure: -20" Hg. to 15 psig.+ (-68 kPa to 103 kPa)
Overpressure: Relief plug opens at approximately 25 psig (172 kPa)
Connections: 1/8"' NPT female high and low pressure taps duplicated - one pair side and one pair back.
Housing: Die cast aluminum. Case and aluminum parts Iridite-dipped to withstand 168 hour salt spray test. Exterior
finish is baked dark gray hammerloid.
Accuracy: Plus or minus 2% of full scale (3% on - 0 and 4% on - 00 ranges), throughout range at 70°F. (21°C)
Standard accessories: Two 1/8" NPT plugs for duplicate pressure taps, two 1/8" pipe thread to rubber tubing adapter and
three flush mounting adapters with screws. (Mounting and snap ring retainer substituted for 3 adapters in MP & HP gage
accessories.)
Weight: 1 lb. 2 oz. (460 g)
* Low temperature models available as special option.
+ For applications with high cycle rate within gage total pressure rating next higher rating is recommended. See Medium and High pressure
options lower left.
OPTIONS AND ACCESSORIES
Transparent overlays
Furnished in red and green to highlight and emphasize critical pressures.
Adjustable signal flag
Integral with plastic gage cover; has external reset screw. Available for most ranges except those with medium or high
pressure construction. Can be ordered with gage or separately.
LED Setpoint Indicator
Bright red LED on right of scale shows when setpoint is reached. Field adjustable from gage face, unit operates on 12 24 VDC Requires MP or HP style cover and bezel.
Portable units
Combine carrying case with any Magnehelic gage of standard range (not high pressure) includes 9 ft. (2.7 m) of 3/16"
I.D. rubber tubing, stand-hang bracket, and terminal tube with holder.
Air filter gage accessory package
Adapts any standard Magnehelic for use as an air filter gage. Includes aluminum surface mounting bracket with screws,
two 5 ft. (1.5 m) lengths of 1/4" aluminum tubing, two static pressure tips and two molded plastic vent valves, integral
compression fittings on both tips and valves.
Quality design and construction features
1. Bezel provides flange for flush mounting in panel.
2. Clear plastic face is highly resistant to breakage. Provides undistorted viewing
of pointer and scale.
3. Precision litho-printed scale is accurate and easy to read.
4. Red tipped pointer of heat treated aluminum tubing is easy to see. It is rigidly
mounted on helix shaft.
5. Pointer stops of molded rubber prevent pointer over-travel without damage.
6. "Wishbone" assembly provides mounting for helix, helix bearings and
pointer shaft.
7. Jeweled bearings are shock-resistant mounted; provide virtually friction-free
motion for helix. Motion damped with high viscosity silicone fluid.
8. Zero adjustment screw is conveniently located in plastic cover, accessible
9.
10.
11.
12.
13.
14.
15.
without removing cover. O-ring seal provides pressure tightness.
Helix is precision milled from an alloy of high magnetic permeability.
Mounted in jeweled bearings, it turns freely to align with magnetic field of
magnet to transmit pressure indication.
Samarium Cobalt magnet mounted at one end of range spring rotates helix without mechanical linkages.
Calibrated range spring is flat spring steel in temperature compensated design. Small amplitude of motion
assures consistency and long life. It reacts to pressure on diaphragm. Live length adjustable for calibration.
Silicone rubber diaphragm with integrally molded O-ring is supported by front and rear plates. It is locked and
sealed in position with a sealing plate and retaining ring. Diaphragm motion is restricted to prevent damage due to
overpressures.
Die cast aluminum case is precision made. Iridite-dipped to withstand 168 hour salt spray test. Exterior finished in
baked dark gray hammerloid. One case size used for all standard pressure ranges, and for both surface and flush
mounting.
Blowout plug of silicone rubber protects against overpressure on 15 PSIG rated models. Opens at approximately
25 PSIG.
"O" ring seal for cover assures pressure integrity of case.
SERIES 2000 MAGNEHELIC® - MODELS AND RANGES
The models listed below will fulfill most requirements. Custom models can be provided for OEM customers. For special
units with scales reading in ounces per square inch, inches of mercury, other metric units, etc., contact the factory.
STOCKED MODELS in bold
Range,
Model
Inches Minor
Number of Water Div.
2000-00 +
2000-0 +
2001
2002
2003
2004
2005
2006
2008
2010
2015
2020
2025
2030
2040
2050
2060
2080
2100
2l50
0-.25
0-.50
0-1.0
0-2.0
0-3.0
0-4.0
0-5.0
0-6.0
0-8.0
0-10
0-15
0-20
0-25
0-30
0-40
0-50
0-60
0-80
0-100
0-150
.005
.01
.02
.05
.10
.10
.10
.20
.20
.20
.50
.50
.50
1.0
1.0
1.0
2.0
2.0
2.0
5.0
Dual Scale Velocity Units
Model
Number
2000-00AV
2000-0AV
2001AV
2002AV
2010AV
Range in W.C.I Minor
Velocity, F.P.M. Div.
0-.25/300-2000
0-.50/500-2800
0-1.0/500-4000
0-2.0/1000-5600
0-10/2000-12500
-
Model
Number
Range
Pascals
2000-60 Pa +
2000-125 Pa +
2000-250 Pa
2000-500 Pa
2000-750 Pa
0-60
0-125
0-250
0-500
0-750
Minor
Div.
2.0
5.0
5.0
10.0
25.0
Zero Center Range
2300-250 Pa
2300-500 Pa
For use with pilot tube.
Model
Number
Range
MM of Water
2000-6MM +
2000-10MM
2000-25MM
2000-50MM
2000-80MM
2000-l00MM
0-6
0-10
0-25
0 50
0-80
0-100
Minor
Div.
.20
.20
.50
1.0
2.0
2.0
Model
Number
125-0-125
250-0-250
Range
Kilopascals
5.0
10.0
Minor
Div.
Range,
Zero
Center
Model
Inches Minor
Number of Water Div.
2300-0 +
2301
2302
2304
2310
2320
2330
.25-0-.25
.5-0-.5
1-0-1
2-0-2
5-0-5
10-0-10
15-0-15
Model
Number
Range
PSI
2201
2202
2203
2204
2205
2210*
2215*
2220*
2230**
0-1
0-2
0-3
0-4
0-5
0-10
0-15
0-20
0-30
.01
.02
.05
.10
.20
.50
1.0
Minor
Div.
.02
.05
.10
.10
.10
.20
.50
.50
1.0
Zero Center Range
2300-20MM +
10-0-10
Model
Number
Range
CM of Water
2000-15CM
2000-20CM
2000-25CM
2000-50CM
2000-80CM
2000-l00CM
2000-150CM
2000-200CM
2000-250CM
2000-300CM
0-15
0-20
0-25
0-50
0-80
0-100
0-150
0-200
0-250
0-300
.50
Minor
Div.
.50
.50
.50
1.0
2.0
2.0
5.0
5.0
5.0
10.0
2000-1 kPa
2000-1.5 kPa
2000-2 kPa
2000-3 kPa
2000-4 kPa
2000-5 kPa
2000-8 kPa
2000-10 kPa
2000-15 kPa
2000-20 kPa
2000-25 kPa
2000-30 kPa
*MP option standard
**HP option standard
.5-0-.5
1.5-0-1.5
.02
.10
Dual Scale English/Metric Models
Zero Center Range
2-0-2
5-0-5
15-0-15
.02
.05
.05
.10
.10
.10
.20
.20
.50
.50
.50
1.0
Zero Center Range
2300-1 kPa
2300-3 kPa
2300-4CM
2300-10CM
2300-30CM
0-1
0-1.5
0-2
0-3
04
05
0-8
0-10
0-15
0-20
0-25
0 30
.10
.20
1.0
Model
Number
2000-0D
2001D
2002D
2003D
2004D
2006D
2008D
2010D
Range
In. W.C.
Range
Pa or kPa
0-0.5
0-1
0-2
0-3
0-4
0-6
0-8
0-10
0-125 Pa
0-250 Pa
0-500 Pa
0-700 Pa
0-1.0 kPa
0-1.5 kPa
0-2.0 kPa
0-2.5 kPa
+ These rages calibrated for vertical scale position.
Accessories
Options
Special Purpose Ranges
A-310A, 3-Way Vent Valve
A-321 Safety Relief Valve
A-432 Portable Kit
A-605 Air Filter Kit
A-610 Pipe mount Kit
ASF (Adjustable Signal Flag)
HP (High Pressure Option)
LT (Low Temperatures to
-20°F)
MP (Med. Pressure Option)
SP (Setpiont Indicator)
Scale No. 2401
Square Root
Scale
Specify Range
Scale No. 2402
Blank Scale
Specify Range
Model 2000-00N
Range: -.05 to
+.20" W.C.
For room
pressure
monitoring
Suggested Specifications
A differential pressure gage for measuring (state purpose) shall be installed. Gage shall be the diaphragm-actuated dial type 4¾" O.D., with
white dial, black figures and graduations and pointer zero adjustment. Gage shall be Dwyer Instruments, Inc., Magnehelic, Catalog No. 2__
reading to __ water column, in. divisions.